Link shared library from another directory

Question

I am building foo.so and that depends on bar.so. They will both be installed in the same location /some/lib, with the RUNPATH set appropriately to /some/lib. But they are built from different directories.

I'm trying to build them like:

cd /tmp/bar
gcc -o bar.o -c bar.c
ld -Bshareable -o bar.so bar.o
cd /tmp/foo
gcc -o foo.o -c foo.c
ld -Bshareable -rpath /some/libs -o foo.so foo.o ../bar/bar.so
ldd foo.so

But the problem is that ldd shows ../bar/bar.so. I can fix it by doing:

cd /tmp/bar
gcc -o bar.o -c bar.c
ld -Bshareable -o bar.so bar.o
cd /tmp/foo
gcc -o foo.o -c foo.c
cp ../bar/bar.so .
ld -Bshareable -rpath /some/lib -o foo.so foo.o bar.so
ldd foo.so

Now the ldd just show plain bar.so, which is right. But is there a better way that doesn't require copying or symlinking bar.so just for the link step?

Answer 1

Solution:

ld -Bshareable -rpath /some/lib -L../bar -o foo.so foo.o -l:bar.so

works without needing to copy bar.so to the current directory.